The present invention relates to agricultural threshing, and more particularly, to the shelling of vegetables such as beans and peas.
Because hand shelling is tedious and time consuming, faster and better methods of shelling green peas, beans and leguminous vegetables are constantly being sought. Many devices have been proposed. However, these devices often produce extensive damage to the peas or beans during the shelling operation, and some of the devices produce sufficient damage to result in the loss of as much as forty to sixty percent of the vegetables. Such high losses reduce profits, and are wasteful of valuable crops. Therefore, there is need of a device which can perform the shelling operation efficiently and with only minimal loss of the crop through damage during that shelling operation.
Many known devices utilize rotating drums as shelling chambers and have impellers or paddles positioned therein to perform the shelling operation. For example, some devices have small bars extending radially outward from rotating drive shafts which are positioned axially within the drums. The bars support variously shaped impellers which serve as the threshing devices, or striking instruments. However, the impellers of these devices often have sharp edges or corners which may strike the pods and often these impellers each present only a limited amount of flat surface area for performing the actual striking operation. The corners or edges can cause great damage to kernels removed from the pods by breaking or bruising those kernels. Because of the small striking surfaces, these devices require the material to remain in the shelling chamber for great lengths of time to remove all the kernels from the pods. The possibility of damage to the kernels increases as the time they spend in the shelling chamber increases.
Another known device utilizes impellers which have striking surfaces oriented at an angle with respect to the longitudinal axis of the rotating shaft to which they are attached. Such a device delivers glancing blows to the material to cause the refuse to move through the shelling chamber in a longitudinal direction. This device also requires a great deal of time to complete a threshing operation and also has exposed sharp edges which may damage the kernels during the shelling operation. Consequently, the loss percentage with this device is also very high.
The device of the present invention has paddles designed to maximize the amount of flat striking surface and which rotate at a prescribed velocity with respect to a rotating cylinder.